Contrast budget of head-mounted displays

This paper introduces the concept of a contrast budget for a head-mounted display, i.e., a list of contrast values of separate contrast-degrading phenomena in the system. The basic phenomena are dynamic range, diffraction, scattered light, and ghost images. By calculating a contrast budget it becomes clear whether or not the display-system contrast will meet specified criteria and which factors contribute the most to the degradation of contrast in the system. An example of a contrast budget is given for the Nomad(TM) head-mounted display system. In this system dynamic range, scanner scattering, and beamsplitter stray light are the dominant contributors, but the overall contrast is comfortably above specification. (C) 2002 Society of Photo-Optical Instrumentation Engineers.